Ski-Doo Summit 800 X Brake Bulb Size

Additional Notes

• The Ski-Doo Summit 800 X uses two distinct brake bulb types across the 2001-2010 model years: the 1157 and the 921, both of which conform to ANSI standards recognized in the United States and Canada.
• The 1157 is the more widely used of the two, appearing in the Summit 800 X for the 2001-2005 and 2008-2010 model years.
• The 1157 is a dual-filament bulb, meaning it contains two separate filaments that operate at different wattages. It runs on 12 volts and draws 21 watts on the primary filament and 5 watts on the secondary, housed in a BAY15d bayonet base.
• The BAY15d bayonet base features two offset pins, a design that prevents the bulb from being seated incorrectly and ensures the correct filament is assigned to the correct circuit.
• The 921 is specified for the 2006-2007 model years. It is a single-filament wedge-type bulb in a T15 form factor, operating at 12 volts and 16 watts.
• The wedge base of the 921 is held in place by tension from the socket itself rather than a locking mechanism, which is a fundamentally different retention method from the BAY15d bayonet base used by the 1157.
• The 1157 and 921 are not interchangeable. Their base types, filament counts, and wattage ratings are all different, making direct substitution between the two incompatible with the original socket and circuit design.
• The single-filament design of the 921 draws a fixed 16 watts, whereas the dual-filament 1157 draws either 5 watts or 21 watts depending on which circuit is active, reflecting a different approach to brake light function between the two model year groups.